The duo of Aaron Taylor-Johnson and Elizabeth Olsen may soon be seen in Gareth Edwards’ Godzilla, but it’s their upcoming roles in The Avengers: Age of Ultronthat has comic book fans on the edges of their seats. As Scarlet Witch and Quicksilver prepare to change Marvel’s flagship franchise forever, the actors promise that they’re doing their homework, and plan on complicating the fight for the rest of the Avengers.

Adding two new heroes to any super-team seems like the kind of move that would be planned out years in advance, but the first hints that Scarlet Witch and Quicksilver would be brought to life came rather unceremoniously, with writer/director Joss Whedon simply stating he had a “brother-sister act” he wanted to introduce. That kind of offhand desire might seem out of place amidst the turbulent world of Marvel movie rumors, but in an interview with iAmRogue, Taylor-Johnson confirmed that the offer was just as informal:

“Just before I started Godzilla I met Joss… He said to me, ‘Do you want to be in Avengers 2? There is a super hero I’m thinking of for you.'”

While the actor didn’t have any reservations or concerns about playing a superhero in a blockbuster film (having some experience as the titular star of Kick-Ass), he explained that the months of speculation surrounding his role in Age of Ultron wasn’t a sign of secrecy or negotiation; he genuinely wasn’t certain the film needed him:

“The thing for me was for [Whedon], ‘Why add any more super heroes to this thing?’ He said, ‘No, there are these two characters that I want to bring in to like f*** with the Avengers and not be just an add on.’ He told me a little bit about the writing and I said that the only reason I would want to do it is if it is a character that can still stand out.

“You know, you’ve got five of the most awesome super heroes, ten I suppose, there are about ten Avengers now, and they are all movie stars… You’ve got such a huge cast, what the hell difference is it going to make if I come on the scene? So it was the character and that took about a year of going back and forth about it. It took a while but I’m super happy to be in that one.”

Fans will be kept in the dark right up until the film’s release (if Marvel has its way), but there’s no question that something will leave fans stunned once the credits roll… or finish rolling. If we were to wager, it seems that the super-powered twins will be right at the heart of it – or even taking the place of those who fall.

Aaron Taylor-Johnson and Elizabeth Olsen in ‘Godzilla’

Superpowers and skyscraper-sized monsters aside, it’s not often that two up-and-coming young actors shift from playing romantic leads (in Godzilla) to twin siblings. While the situation might seem somewhat awkward, Olsen explains that chance to play Wanda and Pietro Maximoff doesn’t just offer the pair a chance to portray a different relationship for audiences, but one which will benefit from their previous work:

“We have a much more closer connection in Avengers actually… Because we play these twin brother and sister that never leave each other’s side. In Godzilla, the whole point is that we are apart. So it’s totally different, but nice to have known him and his family, and him as a person as well as an actor before doing that.”

Although Taylor-Johnson can’t quite predict how the Comic-Con experience will change now that he’s appearing as a fully-fledged superhero, Olsen seems to be jumping into the world of comic book blockbusters with enthusiasm. The actress previously revealed that she has been reading comic books endlessly in preparation, and the first signs of superhero stardom are already beginning to appear:

“It’s awesome to try and create a role that has not been portrayed in live action yet… It’s been cartoons, comics, and video games. It’s fun to take what we are doing, the comics, the cartoon, and the fans, and try to figure it out where you are going to play.

“I didn’t really read any of the feedback. I just have one friend that works at Bad Robot, so she is on all these blogs all the time, and she’ll send me her favorites ones. She only sends me the good stuff but I like that people were stoked about our characters, and everyone was like, ‘What are they? Who are they? What’s their excuse going to be because they can’t talk about X-Men?'”

Every fan is likely just as curious to know how Marvel will handle the issue of the Maximoffs’ lineage – omitting their father (Magneto), or simply re-writing comic fiction? – but the acting credits of both are sure to keep fans more optimistic than usual. And lest we forget, the addition of super-speed and reality-bending ‘magic’ may be overshadowed by the “genuinely disturbed robot” after whom the film is named. Fans have been promised more conflict in Age of Ultron, so even if the pair end up fighting for good (as set photos suggest) they may not start out that way.

How do you feel about the established Avengers being shaken up by the arrival of Scarlet Witch and Quicksilver? Do you have your doubts, or did their post-credits cameo confirm that the film is better off with them included? Sound off in the comments.